Method and apparatus for conserving power consumed by a vending machine utilizing audio signal detection

ABSTRACT

A vending machine that dispenses items for use with a power source. Power control circuitry is electrically coupled between the power source and one or more vending components of the vending machine. A controller is adapted to manage the supply of electrical power to such components by transitioning between a normal-operation mode and at least one power-conserving mode. An audio signal detector is provided that generates at least one dispensing event signal that represents the occurrence of one or more sound-based dispensing events. The controller transitions between the power-conserving mode(s) and the normal-operation mode based upon the at least one dispensing event signal from the audio signal detector, and possibly other data signals supplied to the controller.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of the filing date of U.S.Provisional Application No. 60/544,280 entitled “METHOD AND APPARATUSFOR CONSERVING POWER CONSUMED BY A REFRIGERATED APPLIANCE UTILIZINGAUDIO SIGNAL DETECTION” filed Feb. 12, 2004, the contents of which areincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to refrigerated dispensing appliances and,more particularly, to mechanisms for automatic control of electricalpower supplied to the components of a refrigerated dispensing appliancein a manner that conserves electrical power consumption.

BACKGROUND OF THE INVENTION

Refrigerated dispensing appliances (including vending machines andreach-in type beverage coolers) provide for cost-effective delivery ofconsumer items. In principle, they provide full-time productavailability with minimal intervention by a human operator. However,full-time operation can result in wasted energy consumption as themachine may be on for long intervals of inactivity. The concern forenergy consumption is especially acute in the case of refrigerateddispensing appliances.

Refrigerated dispensing appliances generally maintain their contents ata standard temperature on the order of 36° F. There can be variousreasons for keeping the dispensable items cold. Cold generally helpspreserve perishable food items. In some cases, for example, with sodaand other beverages, the items may taste better chilled.

Typically, the dispensable items are maintained within a chamber that isthermally insulated from the exterior of the machine. A cooling systemwithdraws heat from the chamber. The cooling system can include anevaporator, a compressor, a condenser, and a metering (flowconstricting) device.

When the cooling system is on, coolant liquid, e.g., Freon, enters theevaporator. The evaporator is thermally coupled to the refrigeratedchamber. The coolant liquid is generally colder than the chamber so thatthe coolant removes heat from the chamber. The liquid evaporates as itabsorbs the heat. The evaporated coolant is pumped out of the evaporatorthrough a suction line by a compressor. The compressor increases thepressure of the coolant, raising its temperature in the process. Thepressurized coolant is then directed to a condenser via a dischargeline. The condenser couples the coolant to a chilled environment. Thiscauses the coolant to give up heat and condense into a liquid. Theliquid flows through a liquid line, including the flow meter (which isbasically a flow restriction) back to the evaporator to begin anothercooling cycle. The evaporator removes heat from the nearby chamber air.To ensure that the cool air reaches the dispensable items and to ensurea uniform temperature within the chamber, the chamber air is circulated.Generally, one or more fans are operated within the chamber interior toeffect this circulation.

One or more temperature sensors monitor the temperature inside thechamber. Typically, there is a desired temperature range for the vendeditems, for example, 0° to 2° C. (˜32° F. to 36° F.) for cold drinks.When the chamber temperature reaches the higher threshold, thecompressor is activated and the cooling process begins. When the chambertemperature falls to the lower threshold, the compressor is turned off,and cooling effectively halts. Another cooling cycle can begin when thetemperature reaches the upper threshold due to inevitable heat transferthrough the chamber wall.

Refrigerated dispensing appliances consume considerable electric power.Typically, most of the power consumed by a refrigerated dispensingappliance is consumed by the cooling system, and especially by thecompressor, even though it is not operated continuously. However, thefans, the dispensing mechanism, the money handling mechanisms, panellights, sensors, and control electronics all consume power. For reasonsof energy conservation and cost, it is desirable to be able to reducethe energy consumed by a refrigerated dispensing appliance withoutadversely affecting its service (to patrons) and its economic viability(to the appliance owner).

The most straightforward approach to saving energy is to disconnect ACpower. For example, a refrigerated vending appliance could be turned offduring non-business hours, e.g., from 10 pm to 6 am. To avoid theinconvenience of manual activation and inactivation, an external timercan be used to control AC power to the vending machine. However, whetherpower to the vending machine is switched by a human operator or a timer,potential patrons are denied dispensable items during off hours.Additionally, most artificially-sweetened products deteriorate undersuch temperature cycling. Such temperature cycling also causes cold cansand bottles to “sweat” or develop a water film due to condensation.

Additionally, present cold drink dispensing machines are nearly allelectronically controlled, having internal electronics to controloperation of the cooling and possibly lighting systems, as well as cashcollection and disbursement and possibly non-cash transactions (e.g.credit cards). However, reach-in type beverage coolers, lacking therequirements for cash management, are typically mechanically based,using a simple mechanical thermostat to regulate the operation of itscooling system.

U.S. Pat. No. 6,243,626, to Schanin, commonly assigned to the assigneeof the present invention, discloses an external power control system fora vending machine that includes an occupancy sensor. This can be used toensure a vending machine is on whenever people are in its vicinity. Anambient thermo-sensor can also be included to determine a reactivationtime to prevent the dispensable items from become unacceptably warm.

U.S. Pat. No. 6,389,822 to Schanin, commonly assigned to the assignee ofthe present invention, discloses a refrigerated soda vending machinethat includes temperature sensors for monitoring temperature within itsrefrigerated chamber and temperature of the ambient air external to thechamber, and an occupancy sensor for monitoring occupancy in thevicinity of the chamber. The sensor data is used to determine when toswitch between a normal-operation mode and a power-conservation mode ofoperation. In the normal mode of operation, fans circulate air withinthe chamber to maintain a relatively uniform temperature throughout thechamber. During power-conservation mode, the fans are off most of thetime the compressor is off. In the absence of circulation, thetemperature within the refrigerated chamber stratifies so that a lowercool zone and an upper warm zone can be differentiated. Cold drink cansor bottles are held in vertical stacks so that the lowest product islocated in the cool zone. Product is dispensed from the bottom of thestacks and thus only from the cool zone. The machine automaticallyswitches from the power-conserving mode to the normal mode in the eventthat the occupancy sensor senses occupancy in the vicinity of themachine. With this arrangement, a patron can obtain an optimally chilledproduct even though the average temperature in the chamber is above theoptimal temperature range. Thus, energy can be conserved and operatingcosts reduced while meeting patron's expectations for cold beverages atall times.

While these power-saving control mechanisms are effective in that thereis no risk of lost sale due to a customer believing the machine isnon-operational, such mechanisms may be inefficient in circumstanceswhere people walking in the vicinity of the machine are not interestedin buying products. In such circumstances, exiting the power-conservingmode based on occupancy is not efficient.

SUMMARY OF THE INVENTION

The present invention includes a refrigerated dispensing appliance foruse with a power source and comprising a cooling system. Power controlcircuitry is electrically coupled between the power source (e.g., powercord coupled to a wall outlet) and components (for example, a compressorand one or more circulating fans of the cooling system) of theappliance. A controller is adapted to control the power controlcircuitry to manage the supply of electrical power to such components byintelligently transitioning between a normal-operation mode and at leastone power-conserving mode. To achieve efficient power conservation, anaudio signal detector is provided that generates at least one dispensingevent signal that represents the occurrence of one or more sound-baseddispensing events. The controller automatically transitions between thepower-conserving mode(s) and the normal-operation mode based upon atleast one dispensing event data signal supplied to the controller by theaudio signal detector.

The dispensing event data signals are indicative of one or morepredetermined dispensing events that occur during dispensing operations.Such dispensing events depend upon the location of the pickup device ofthe audio signal generator. For example, the pickup device may bedisposed in the vicinity of a dispensing port to sense items passingtherethrough. In another example, the pickup device may be disposed inthe vicinity of a customer-access delivery mechanism to sensemanipulation of the customer-access delivery mechanism by a patron. Inyet another example, the pickup device may be disposed in the vicinityof mechanized devices (e.g., motorized actuators) that select productduring dispensing operations to sense operation of the mechanizeddevices.

According to one embodiment of the present invention, the refrigerateddispensing appliance is a refrigerated beverage vending machine havingthe intelligent power-management controller that performsnormal-operating mode cooling control operations in addition topower-conserving mode cooling operations.

In another embodiment of the present invention, the intelligentpower-management controller is part of a module that interruptsnormal-operating mode cooling operations performed by a machinecontroller to provide power-conserving mode cooling control of therefrigerated beverage vending machine.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is best understood from the following detailed descriptionwhen read in connection with the accompanying drawing. It is emphasizedthat, according to common practice, the various features of the drawingare not to scale. On the contrary, the dimensions of the variousfeatures are arbitrarily expanded or reduced for clarity. Included inthe drawing are the following figures:

FIG. 1 is a schematic view of a refrigerated beverage vending machine inaccordance with an exemplary embodiment of the present invention;

FIG. 2 is a block diagram of an exemplary control system of therefrigerated beverage vending machine of FIG. 1 in accordance with anexemplary embodiment of the present invention;

FIG. 3 is a schematic diagram of an exemplary embodiment of the audiosignal detection circuitry of FIG. 2;

FIG. 4 is a schematic diagram of another exemplary embodiment of theaudio signal detection circuitry of FIG. 2;

FIG. 5 is a schematic block diagram of yet another exemplary embodimentof the audio signal detection circuitry of FIG. 2; and

FIG. 6 is a flow chart of an exemplary power-management control schemecarried out by the control system of FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

Turning now to FIG. 1, a refrigerated beverage vending machine 10 inaccordance with the present invention includes a housing 11 with a frontpanel 13. Front panel 13 comprises coin slot 15 and bill slot 17,selection buttons B1, B2, B3, and B4, coin return slot 19, and dispensedbeverage slot 21. Typically, a patron inserts a suitable amount of moneyin coin slot 15 and/or bill slot 17, depresses a selection button B1-B4,and receives a container of the selected beverage from slot 21. If thepatron inserts more than the required amount for purchase, vendingmachine 10 provides change at coin return slot 19. Power for vendingmachine 10 is provided through power cord 23 plugged into an electricoutlet 24 that supplies an AC power signal (e.g., 120 volt AC signal).

Beverage dispensing mechanism 25 holds beverage containers (e.g., cans)in four vertical stacks (one stack 27 shown). Each stack is intended tohold the type of beverages indicated by a respective one of theselection buttons B1-B4; for example, depressing button B1 serves as arequest for an item from stack 27. In stack 27, nine exemplarycontainers C1-C9 are stacked. When a patron depresses button B1,dispensing mechanism 25 dispenses beverage container C1. The remainingcontainers C2-C8 then move down, assisted by gravity, one containerposition each. Dispensing mechanism 25 and the containers it holds arelocated within a chamber 30 that is desirably thermally insulated fromits exterior by insulation 32.

A cooling system 40 is used to keep chamber 30 and its contents nearfreezing so that the beverage containers disposed therein are optimallychilled. Cooling system 40 comprises evaporator 41, suction line 43,compressor 45, discharge line 47, condenser 49, and flow meter 51located along liquid line 53. Evaporator 41 is located within chamber 30and withdraws heat therefrom. The remaining components of cooling system40 serve to recycle the coolant so that it can remove heat continuouslyfrom chamber 30.

Cooling system 40 primarily cools the air near evaporator 41. Fans F1and F2 circulate air within chamber 30 so that the cool air chills thecontainers and their contents. In addition, this circulation ensures arelatively uniform temperature distribution, i.e., a relatively lowtemperature variance, within chamber 30. As shown in FIG. 2, the coolingsystem 40 also includes power control circuitry 46A and 46B, that areoperably disposed between the power source (e.g., power cord 23 that isplugged into outlet 24) and the compressor 45 and the circulating fansF1 and F2, respectively. The power control circuitry 46A, 46B (which maybe realized by relays or other power switching devices) switch on andoff the supply of power to the compressor 45 and the circulating fans F1and F2, respectively, in response to control signals supplied by thecooling system controller 74 as described below in more detail.

Referring again to FIG. 1, vending machine 10 includes control subsystem60 that controls dispensing of beverage containers by the dispensingmechanism 25 and controls the supply of power to the cooling system 40to provide for automatic power conservation. FIG. 2 illustrates afunctional block diagram of the control subsystem 60 of the exemplaryrefrigerated vending machine of FIG. 1. As shown in FIG. 2, controlsubsystem 60 includes two control modules 60 a and 60 b. First controlmodule 60 a includes machine controller 62 that is responsible forcontrolling dispensing operations and for normal-operation mode coolingoperations. Second control module 60 b includes an energy saving coolingsystem controller 74 that is responsible for managing supply of power toelectrical components (including the fans F1 and F2 and the compressor45 of the cooling system 40) of vending machine 10 in the power-savingmode of operation in accordance with the power control operations of thepresent invention.

Machine controller 62 is operably coupled to at least one money handlingmodule 64. Each money handling module 64 recognizes and validatescurrency supplied thereto (e.g., coins or bills inserted through slots15, 17), generates data that provides an indication of the validatedcurrency supplied thereto, and communicates such data to dispensingcontroller 62 over communication bus 66 therebetween. For example, therefrigerated vending machine 10 of FIG. 2 includes two money handlingmodules: a coin acceptor/validator/changer module 64A coupled to themachine controller 62 over communication bus 66; and a billacceptor/validator module 64B coupled to the machine controller 62 overcommunication bus 66. The vending machine 10 may include additionalmoney handling modules (not shown), such as a smart card reader thatreads currency data stored in a smart card and/or a prepaid cash card.As shown in FIG. 2, communication bus 66 is a common bus operablycoupled to multiple money handling modules. The common bus desirablycomprises a serial multi-drop bus (MDB) commonly used in the vendingarts. Alternatively, separate buses (or other data communicationmechanisms) may be operably coupled to the money handling modules.

Machine controller 62 is operably coupled to system memory 68, which istypically realized with both at least one persistent memory module, suchas a Flash memory module or EEPROM memory module, and at least onenon-persistent memory module, such as a DRAM memory module or an SRAMmodule. The system memory 68 persistently stores a dispensing controlroutine 70 that is loaded by the machine controller 62 for executiontherein. Dispensing control routine 70 includes a sequence ofinstructions that, when executed by the machine controller 62, monitorthe data signals supplied by each money handling module 64 overcommunication bus 66 therebetween to count the amount of currencysupplied by the patron and provide any change, if necessary. When thecorrect amount of currency has been supplied, dispensing controller 62monitors the status of the selection buttons B1-B4. When the userselects one of buttons B1-B4, machine controller 62 controls dispensingmechanism 25 to dispense a beverage container corresponding to theselected button to dispensing slot 21. Machine controller 62 may alsointerface to display 72 (such as an LED or LCD display for example) inorder to provide status information during the dispensing operations orto provide other information to the patron (or potential patron).

Machine controller 62 is operably coupled to temperature sensor T1 andoperably coupled to compressor power control circuitry 46B as shown.Temperature sensor T1 provides an indication of the internal temperatureof cavity 30 (see FIG. 1) of vending machine 10. Compressor powercontrol circuitry 46B, which may be realized by a relay or other powerswitching device, is operably coupled between the power source (e.g.,outlet 24 and cord 23) and compressor 45 of the machine's cooling system40. Compressor power control circuitry 46B operates in either an on oroff condition. In its on condition, compressor power control circuitry46B electrically couples the power source to compressor 45. In its offcondition, compressor power control circuit 46B electrically decouplescompressor 45 from the power source. Compressor power control circuitry46B has a control input that is coupled to machine controller 62.Through its connection to the control input, machine controller 62 isable to control when the compressor power control circuit 46B is in itson condition and when it is in its off condition.

In addition, system memory 68 persistently stores a normal-operationmode cooling routine 80 a. The normal-operation mode cooling routine 80a includes a sequence of instructions that, when executed by the machinecontroller 62, monitors the data signals provided by temperature sensorT1 (and possibly other data signals) and switches the compressor powercontrol circuitry 46B on and off in order to maintain the desiredinternal temperature of chamber 30.

As described above, second control module 60B is responsible forrealizing power-conserving mode cooling control of the vending machine10. It includes cooling system controller 74 that is operably coupled tosystem memory 78, ambient temperature sensor T2, timer circuitry 76,voltage sensor 77, fan power control circuitry 46A and compressor powercontrol circuitry 46B as shown. In addition, the controller 74 isoperably coupled to audio signal pickup device 79 (such as a microphoneor other transducer device) via audio signal detection circuitry 81 asshown. Audio signal pickup device 79 is located with the machine 10 suchthat it “hears” sounds related to dispensing events that occur duringthe dispensing operations of machine 10. For, example, the audio signalpickup device 70 may be located:

i) near a discharge chute through which the product passes during asale;

ii) near mechanized devices (such as motors or other actuators) thatselect and/or delivers a desired product from an offering of products;and/or

iii) near a customer-access delivery mechanism for the machine, which istypically realized by a small door that prohibits theft and the entry ofelements and small animals.

Audio signal detection circuitry 81 processes the signal provided bypickup device 79 (which is typically a low level signal) to amplify (andpossibly filter) the signal to a level that is suitable for use by thecontroller 74. Details of exemplary embodiments of the audio signaldetection circuitry 81 are set forth below in FIGS. 3-5.

Fan power control circuitry 46A, which may be realized by a relay orother power switching device, is operably coupled between the powersource (e.g., outlet 24 and cord 23) and circulating fans F1 and F2 ofthe machine's cooling system 40. The fan power control circuitry 46Aoperates in either an on or off condition. In its on condition, fanpower control circuitry 46A electrically couples the power source to thecirculating fans. In its off condition, fan power control circuit 46Aelectrically decouples the fans from the power source. Fan power controlcircuitry 46A has a control input that is coupled to cooling systemenergy saving controller 74. Through its connection to the controlinput, controller 74 controls when the fan power control circuit 46A isin its on condition and when it is in its off condition.

As described above, compressor power control circuit 46B operates ineither an on or off condition to selectively supply power to compressor45. Through a connection to a control input of circuit 46B, coolingsystem energy savings controller 74 is able to control when compressorpower control circuit 46B is in its on condition and when it is in itsoff condition.

System memory 78 persistently stores a power-savings mode cooling systemcontrol routine 80 b. Power savings mode cooling system control routine80 b includes a sequence of instructions that, when executed bycontroller 74, monitors the data signals provided by ambient temperaturesensor T2, timer circuitry 76, voltage sensor 77, and audio signaldetection circuitry 81. In response to these signals, controller 74controls power control circuit 46 to automatically switch on and off thesupply of electrical power to components (e.g., cooling fans F1/F2 andthe compressor 45 of cooling system 40 and possibly other electricalcomponents) of machine 10 to keep the beverages in the chamber of thevending machine 10 cool while minimizing the energy consumed by thecooling system 40, and thus provide valuable energy savings.

As described above, cooling system controller 74 monitors the signalsprovided by audio signal detection circuitry 81, and switches the on/offoperating modes of components of cooling system 40 based upon thesesignals. Such signals are indicative of sounds related to dispensingevents that occur during the operation of machine 10. Such dispensingevents may include, for example, the delivery of product to a deliverylocation, the selection of one desired product from an offering of manyproducts, customer access of a delivery mechanism (e.g., access door).These events occur every time a product (e.g., can or bottle) isdispensed from machine 10.

In the control architecture of FIG. 2, two separate controllers (62 and74) perform the normal-operation mode cooling control and thepower-saving mode cooling control, respectively. In this configuration,both controllers 62 and 74 control the supply of power to compressor 45via control signals output to compressor power control circuit 46B. Toprovide for maximal power savings, it is desirable that energy savingcontroller 74 have the ability to selectively disable thenormal-operation mode cooling operations performed by machine controller62. This may be accomplished, for example, by adapting power controlcircuitry 46B such that the energy-savings mode compressor ON/OFFcontrol signals supplied thereto by the energy saving controllerselectively override (e.g., selectively disable) the normal-operationmode compressor ON/OFF power supply control signals supplied thereto bymachine controller 62. This control override feature occurs in responseto a control signal (e.g., normal-operation mode enable/disable signal)supplied to the compressor power control circuit 46B by energy savingcontroller 74.

It is also desirable that the power-saving mode cooling operations beginupon completion of a compressor-on cooling cycle performed by machinecontroller 62. To automatically sense the completion of suchcompressor-on cooling cycles, voltage sensor 77 is provided. As shown inFIG. 2, voltage sensor 77 is operably coupled to the control linebetween machine controller 62 and the corresponding control input ofcompressor power control circuit 46B. The data signals generated byvoltage sensor 77 are monitored by cooling system energy savingcontroller 74 in order to identify completion of the compressor-oncooling cycles performed by machine controller 62.

Turning now to FIG. 3, there is shown an exemplary realization of audiosignal detection circuitry 81 of FIG. 2. The circuitry includes a biasresistor R3 (for example, on the order of 2.5 kOhms) coupled between apositive voltage supply (e.g., 5 Volts) and the positive lead L1 of themicrophone pickup device (labeled “micro1”). The negative lead L2 of themicrophone pickup device micro1 is coupled to ground. The microphonepickup device is preferably an electret condenser microphone cartridge,such as the Panasonic WMO34 DB model microphone cartridge. A capacitorC1 (for example, on the order of 22 pF) may be coupled between thepositive lead L1 and ground for filtering out unwanted high frequencycomponents generated at the positive lead L1 of the microphone pickupdevice. A coupling capacitor Cc (for example, on the order of 27 pF) iscoupled between the positive lead L1 and an amplification stage 301 forDC isolation therebetween. The amplification stage 301 is realized by anoperation amplifier configured as a non-inverting amplifier as is wellknown in the electronic arts. In this configuration, the non-invertinggain of the stage 301 is dictated by the ratio of ((R1+R2)/R2), which ison the order 38 for the exemplary resistor values shown in FIG. 3. Aresistor R4 (preferably on the order of 5 Kohm) is coupled between thepositive input of the operational amplifier and ground potential toprovide a ground potential DC reference thereto. A capacitor C2 may beadded in parallel with the resistor R1 as part of the feedback path ofthe amplification stage 301 as shown to improve the stability of theamplifier stage 301 to filter out unwanted frequency components.

The output of the amplification stage 301 is supplied to digitaldetector 305 (typically realized by a comparator) that outputs a digital“H” value when the voltage level of the signal supplied thereto from theamplification stage 301 exceeds a predetermined reference level andoutputs a digital “L” value when the voltage level of the signalsupplied thereto from amplification stage 301 does not exceed thepredetermined reference level. The reference level may be provided by aresistor divider network or other voltage reference circuit as is wellknown in the electronic arts. The digital signal values generated bydetector 305 are supplied to controller 74 for use in the controlmethodology as described herein.

Turning now to FIG. 4, there is shown another realization of audiosignal detection circuitry 81 of FIG. 2. This circuitry employs twoamplification stages to provide large signal gain. The circuitryincludes a bias resistor R13 (for example, on the order of 2.7 kOhms)coupled between a positive voltage supply (e.g., 5 Volts) and thepositive lead L1 of the microphone pickup device (labeled “micro1”). Thenegative lead L2 of the microphone pickup device is coupled to ground.The microphone pickup device is preferably an electret condensermicrophone cartridge as described above. A capacitor C11 (for example,on the order of 22 pF) may be coupled between the positive lead L1 andground for filtering out unwanted high frequency components generated atthe positive lead L1 of the microphone pickup device. A couplingcapacitor Cc (for example, on the order of 0.01 pF) is coupled betweenthe positive lead L1 and a first amplification stage 401 for DCisolation therebetween. The first amplification stage 401 is realized byan operation amplifier configured as a non-inverting amplifier as iswell known in the electronic arts. In this configuration, thenon-inverting gain of the stage 401 is dictated by the ratio of((R14+R15)/R15), which is on the order of 201 for the exemplary resistorvalues shown in FIG. 4. A resistor R16 (preferably on the order of 5Kohm) is coupled between the positive input of the operational amplifierand ground potential to provide a ground potential DC reference thereto.A capacitor C17 may be added in parallel with the resistor R14 as partof the feedback path of the amplification stage 401 as shown to improvethe stability of the amplifier stage 401 and filter out unwantedfrequency components.

The output of first amplification stage 401 is supplied to secondamplification stage 403, which is realized by an operation amplifierconfigured as a non-inverting amplifier as is well known in theelectronic arts. In this configuration, the non-inverting gain of thestage 403 is dictated by the ratio of (((R19+R20)/R20), which is on theorder of 201 for the exemplary resistor values shown in FIG. 4. Aresistor R21 (preferably on the order of 5 kOhms) is coupled between thepositive input of the operational amplifier and ground potential toprovide a ground potential DC reference thereto. A resistor R17(preferably on the order of 15 Kohm) and capacitor C18 (preferably onthe order of 22 uF) are series coupled between the output of the firststage 401 and the positive input of the operational amplifier to provideAC coupling (DC isolation) between the two stages. One or morecapacitors (for example, two capacitors C22 and C23 each on the order of0.01 pF as shown) may be added in parallel with the resistor R19 as partof the feedback path of the amplification stage 403 as shown to improvethe stability of the amplifier stage 403 and filter out unwantedfrequency components.

The output of second amplification stage 403 is supplied to digitaldetector 405 (typically realized by a comparator) that outputs a digital“H” value when the voltage level of the signal supplied thereto from theamplification stage 403 exceeds a predetermined reference level andoutputs a digital “L” value when the voltage level of the signalsupplied thereto from amplification stage 403 does not exceed thepredetermined reference level. The reference level may be provided by aresistor divider network or other voltage reference circuit as is wellknown in the electronic arts. The digital signal values generated bydetector 405 are supplied to controller 74 for use in the controlmethodology as described herein.

In the embodiment described above with respect to FIGS. 3 and 4, theamplification gain is selected to provide ambient noise amplificationthat does not exceed the reference level of the digital detector. Notethat the circuitry amplifies all noise, and in particular any noisegenerated by the operation of the cooling system 40 will be amplified.Therefore, it is possible that the amplified output resulting from suchnoise will exceed the reference level of the digital detector, andtherefore potentially cause erroneous operation. However, because thecontroller 74 also controls the machine's cooling system, it can readilybe adapted to ignore the signals generated by the digital detector whilethe cooling system is running.

In some applications, the circuitry of FIGS. 3 and 4 cannot be usedsuccessfully because the environment in which the machine is located isnoisy in its own right. For example, the circuitry of FIGS. 3 and 4 maybe unsuitable for outdoor locations or indoor locations in loud ambientnoise environments (such as a factory). In addition, variations in theinstallation of the microphone, as well as machine to machine variationsand changes that occur to the machines as they age, can cause theintensity of the sound to vary significantly. In these applications, theamplified output resulting from such ambient noise levels will likelyexceed the reference level of the digital detector, and thereforepotentially cause erroneous operation.

Turning now to FIG. 5, there is shown an exemplary realization of theaudio signal detection circuitry 81 of FIG. 2. The circuitry of FIG. 5self-adjusts to eliminate background noise, while still detecting fastrate audio signals that are indicative of vending sales. Thus, suchcircuitry is suitable for loud ambient noise environments, and addressesmany of the limitations of the circuitry of FIGS. 3 and 4 as discussedabove. The circuitry of FIG. 5 includes a bias resistor R33 coupledbetween a positive voltage supply (e.g., 5 Volts) and the positive leadL1 of the microphone pickup device (labeled “micro1”). The negative leadL2 of the microphone pickup device is coupled to ground. The microphonepickup device is preferably an electret condenser microphone asdescribed above. A capacitor C31 (for example, on the order of 22 pF)may be coupled between the positive lead L1 and ground for filtering outunwanted high frequency components generated at the positive lead L1 ofthe microphone pickup device. A coupling capacitor Cc is coupled betweenthe positive lead L1 and first amplification stage 501.

First amplification stage 501 is realized by a first operationalamplifier 503 configured as an inverting amplifier as is well known inthe electronic arts. In this configuration, the first operationalamplifier 503 provides a gain value dictated by the ratio of (−R34/R35),which is on the order −200 for the exemplary resistor values shown inFIG. 5. A second operational amplifier 505 is operably coupled in thefeedback path from the output node of the first operational amplifier503 to the positive terminal of the first operational amplifier 503 asshown. The second operational amplifier 505 is configured as anintegrator/low-pass-filter stage that filters out the higher frequencyimpulse signal but allows the lower frequency ambient noise signal levelto pass through the feedback path. The characteristic time constant (andpole) of the second operational amplifier 505 is dictated by the ratio(R36/C37), which is selected to filter out the higher frequency impulsesignal components and pass the lower frequency ambient noise signallevel. In this configuration, the second operational amplifier 505integrates the difference between the ambient noise signal level (whichis produced by the first stage operational amplifier 503) and areference node voltage level (which may be provided by a resistordivider network or other voltage reference circuits as is well known inthe electronic arts). When this difference signal increases, the outputof the second operational amplifier 505 drives the voltage level at thepositive terminal of the first operational amplifier 503 higher. Thisfeedback operation continues such that the voltage level at the positiveterminal of the first operational amplifier 503 tracks the ambient noiselevel. In this manner, the two operational amplifier circuits 503 and505 cooperate to cancel out the effect of ambient noise. Any impulsesound signal greater than the ambient noise level is amplified by thefirst operational amplifier circuit 503. One or more capacitors (notshown) may be added in parallel with the resistor R34 as part of thenegative feedback path of the first amplification stage 501 to providestability and desired filtering as described above. The output of firstamplification stage 501 is supplied to second amplification stage 507.

Second amplification stage 507 is realized by operational amplifier 509that is also configured as an inverting amplifier. In thisconfiguration, operational amplifier 509 provides a gain value dictatedby the ratio of (−R38/R39), which is on the order −200 for the exemplaryresistor values shown in FIG. 5. A positive voltage reference (labeled“Vref”), which may be provided by a resistor divider network or othervoltage reference circuits as is well known in the electronic arts, isoperably coupled to the positive terminal of operational amplifier 509to provide a positive potential DC reference. One or more capacitors(not shown) may be added in parallel with the resistor R38 as part ofthe negative feedback path of second amplification stage 507 to providestability and desired filtering as described above.

The output of second amplification stage 507 is supplied to digitaldetector 511 (typically realized by a comparator) that outputs a digital“H” value when the voltage level of the signal supplied thereto fromamplification stage 507 exceeds a predetermined reference voltage level,and outputs a digital “L” value when the voltage level of the signalsupplied thereto from amplification stage 507 is less than thepredetermined reference voltage level. The reference voltage level maybe provided by a resistor divider network or other voltage referencecircuits as is well known in the electronic arts. The digital signalvalues generated by detector 511 are supplied to controller 74 for usein the control methodology as described herein.

Advantageously, the audio signal detection circuitry described abovewith respect to FIG. 5 cancels out the effect of ambient noise and isable to accurately detect impulse sound signals in loud ambient noiseenvironments.

While the algorithm used for entering, exiting, and transitioningbetween normal-operation mode and the power-conservation mode(s) isprogrammable, the default program determines the mode based on ambienttemperature (i.e., temperature of the environment where machine 10 islocated) and dispensing events that occur during dispensing operationsperformed by vending machine 10.

An exemplary control methodology realized by the control module 80 b inaccordance with the present invention is illustrated in the flow chartof FIG. 6. Initially, the control operations enter the normal-operationmode in step S40. In step S40, the normal-operation mode coolingoperations are enabled (for example, by supplying the normal-operationmode enable signal to compressor power control circuitry 46B).Preferably, as part of the normal-operation mode cooling operations, thecompressor of the cooling system is cycled on for a period of time whenthe internal temperature of chamber 30 exceeds a high threshold internaltemperature to thereby cool chamber 30.

In step S42, the time from the last dispensing event, which is providedby timer circuitry 76, is monitored to determine if this time is greaterthan a predetermined maximum time (e.g., 15 minutes). If not, thecooling system control routine remains in the normal-operation mode andreturns back to step S42 to monitor the time from the last dispensingevent; otherwise the operation jumps to step S44 as shown.

In step S44, a determination is made whether machine controller 62 is inan active cooling cycle (for example, by monitoring the data signalsupplied by voltage sensor 77). If so, the process returns to step S44to wait until the active cooling cycle ends; otherwise the processcontinues to the power-saving mode in step S45.

In step S45, the normal-operation mode cooling operations are disabled(for example, by supplying the normal-operation mode disable signal tothe compressor power control circuitry 46B). As a result, the compressorpower ON/OFF control signals generated by machine controller 62 areignored. The process continues to step S46.

In step S46, power-savings mode cooling system control routine 80 bcooperates with compressor power control circuitry 46B to deactivatecompressor 45. In addition, power-savings mode cooling system controlroutine 80 b preferably cooperates with the fan power control circuitry46A to deactivate circulating fans F1 and F2 to provide maximal powersavings. The process then continues to step S47.

In step S47, the compressor_off_timer is set to a predetermined timeperiod, and the process proceeds to step S59. In step S59, adetermination is made to ensure that the compressor_off_timer hasexpired. If the timer has not expired, the control routine waits in stepS59 until the compressor_off_timer expires, and then proceeds to stepS48.

In step S48, the Shutdown Countdown Timer is started, and the processproceeds to step S50.

In step S50, parameters including the shutdown timer, ambienttemperature provided by temperature sensor T2 and possibly otherparameters and data signals are monitored. For example, an additionalparameter may be used to provide an indication that additionalpower-saving mode cooling cycles are required to be executed. At blockS52, if it is found that the parameter values call for activatingcooling system 40, the process continues to step S54; otherwise, theprocess jumps to step S60 as described below.

In step S54, compressor 45 and circulating fans F1 and F2 are turned on(via cooperation between power-savings mode cooling system controlroutine 80 b power control circuitry 46A, 46B) to activate the supply ofpower to the fans and the compressor, respectively, and the processproceeds to S56. In step S56, the dispensing event data signals aremonitored to determine if there is an occurrence of a predetermineddispensing event. As described above, the occurrence of thepredetermined dispensing event generates sound signals related theretoduring the operation of machine 10. Such dispensing events may include,for example, the delivery of product to a delivery location, theselection of one desired product from an offering of many products,customer access of a delivery mechanism (e.g., access door). Theseevents occur every time a product (such as a container, can or bottle)is dispensed from machine 10 in accordance with the dispensingoperations controlled by machine controller 62. If the occurrence of apredetermined dispensing event data signal is identified in step S56,the process exits the power-conservation mode and jumps to thenormal-operation mode which begins at step S40; otherwise the processcontinues to step S58.

In step S58, a determination is made if the current cooling cycle iscomplete. The completion of the current cooling cycle can be based uponany number of parameters such as ambient temperature, internal chambertemperature, elapsed time, etc. If it is determined that the currentcooling cycle is not complete, the process returns to step S56 tomonitor the dispensing event signals. However, if it is determined thatthe current cooling cycle is complete, the process returns to step S45to begin another cooling cycle in the power-conservation mode.

Returning to step S52, if the parameter values do not call foractivating the cooling system, the process jumps to step S60. In stepS60, as in step S56, the dispensing event data signals are monitored todetermine if there is an occurrence of a predetermined dispensing event.If the predetermined dispensing event has not occurred, the processreturns back to step S50 to monitor parameters for turn on. However, ifthe dispensing event has occurred, the process returns to step S40 andthe normal-operation mode resumes.

Note that the parameter values (e.g., shutdown timer value, ambienttemperature, etc.) that trigger switching the cooling system on in stepsS50 to S54 of the power-conservation mode are selected such thattemperature stratification occurs within the appliance, which allows theinternal temperature of the appliance to be maintained at a higheraverage temperature than in the normal-operation mode. Due totemperature stratification, a portion of the chamber (e.g., a locationwithin the chamber from which containers will soon be dispensed) willremain at a desired temperature for longer periods of time withoutcooling. Such operations save energy in several ways. First, the coolingcycles are less frequent, which reduces the number of times the coolingsystem has to start up and thus saves energy involved in starting up thecooling system. In addition, there is less heat transfer from theexterior while the average internal temperature is elevated. Finally,energy is saved while the circulating fans are off as less energy isused and less heat from fan motor(s) is dissipated into the refrigeratedchamber. Moreover, because the control operations automatically exit thepower-conservation mode and return to the normal-operation mode whenvending machine 10 is actively dispensing product, vending machine 10maintains a cooler average temperature of chamber 30 when vendingmachine 10 is actively dispensing product (as compared to the averagetemperature of chamber 30 when the vending machine has been inactive indispensing beverages for a predetermined time interval, e.g., thepredetermined maximum time period in step S18). This ensures thatpatrons receive product at the desired temperature.

The operation of the power-savings mode cooling system control routine80 b is programmable. The predetermined maximum time period in step S42can be adjusted. In addition, the energy savings controller 74 mayinterface to other sensors that can be used in controlling the mode ofoperation. For example, an absolute-time sensor, such as time-of-yearsensor TOY, can be used to affect vending machine behavior at certaintimes of the day, on certain days of the week, and certain holidays, oran ambient temperature sensor external to the vending machine and/or anoccupancy sensor can be used to control the mode of operation.

There have been described and illustrated herein several embodiments ofrefrigerated appliances and power control modules/methodologies usedtherein that intelligently manage the supply of power to components ofthe cooling system of such appliances such that proper operatingtemperature is maintained while energy is conserved. While particularembodiments of the invention have been described, it is not intendedthat the invention be limited thereto, as it is intended that theinvention be as broad in scope as the art will allow and that thespecification be read likewise. Moreover, while particularconfigurations of control architectures and schemes have been disclosed,it will be appreciated that other configurations could be used as well.For example, and not by way of limitation, it is contemplated that thecontrol schemes can automatically transition between thenormal-operating mode and more than one power-saving mode of operation.Such power-saving modes might activate cooling based upon differentambient temperature levels. Alternatively, such power saving modes maybe based on dynamic modulation of the power supplied to the coolingsystem components (e.g., circulating fan motor, compressor, etc). Itwill therefore be appreciated by those skilled in the art that yet othermodifications could be made to the provided invention without deviatingfrom its spirit and scope as claimed.

1. A vending machine for dispensing at least one vending item,comprising: a vending component within the vending machine; circuitryfor supplying power to the vending component; an audio signal detectorfor detecting an audio signal indicating the at least one vending itemis being dispensed and for transmitting a dispensing event signal inaccordance with the detected audio signal; and a controller forreceiving the dispensing event signal from said audio signal detectorand for controlling said circuitry to transition between first andsecond operating modes based on the received dispensing event signal,wherein in the first operating mode the circuitry supplies power to thevending component and in the second operating mode the circuitry cutsoff power to the vending component.
 2. The vending machine according toclaim 1, wherein said controller is adapted to transition from thesecond operating mode to the first operating mode responsive to thedispensing event signal indicating the at least one vending item isbeing dispensed.
 3. The vending machine according to claim 1, furthercomprising: a timer for measuring an elapsed time from a last dispensingevent indicated by said dispensing event signal such that the firstoperating mode is transitioned to the second operating mode responsiveto the elapsed time exceeding a predetermined threshold.
 4. The vendingmachine according to claim 1, further comprising: a dispensing unit fordispensing the at least one vending item and for generating one or moresound-based dispensing events indicating that the at least one vendingitem is being dispensed, the dispensing unit including at least one of:(1) a dispensing port through which the vending item to be dispensed ispassed for delivery; (2) an access unit that is operated for delivery ofthe vending item to a patron; or (3) a mechanized unit that selects thevending item from a plurality of vending items.
 5. The vending machineaccording to claim 4, wherein the audio signal detector includes asound-based event detector disposed in a vicinity of one or more of thedispensing port, the access unit or the mechanized unit to sense soundgenerated by the dispensing unit during a respective sound-baseddispensing event.
 6. The vending machine according to claim 1, whereinthe audio signal detector includes a noise compensation unit thatcompensates for ambient noise, the noise compensation unit dynamicallychanging a level of the detected audio signal that indicates adispensing event based on changes in ambient noise level.
 7. The vendingmachine according to claim 6, wherein the noise compensation unitincludes first and second amplifier such that the second amplifier iscoupled to an output of the first amplifier to generate a feedbacksignal for one input of the first amplifier, a level of the feedbacksignal corresponding to the ambient noise level.
 8. The vending machineaccording to claim 1, wherein the vending component includes at leastone of: a compressor, a circulating fan, or a cooling system.
 9. Thevending machine according to claim 1, wherein the controller is adaptedto automatically transition from the second operating mode to the firstoperating mode based on at least one of an ambient temperature, aninternal temperature or a shutdown timer value indicating power to thevending unit is to be restored.
 10. A power management system for avending component within a vending machine that dispenses vending items,comprising: circuitry for supplying power to the vending component; anaudio signal detector for detecting an audio signal indicating arespective vending item is being dispensed and for transmitting adispensing event signal in accordance with the detected audio signal;and a controller for receiving the dispensing event signal from saidaudio signal detector and for controlling said circuitry to transitionbetween first and second operating modes based on the receiveddispensing event signal, wherein in the first operating mode thecircuitry supplies power to the vending component and in the secondoperating mode the circuitry cuts off power to the vending component.11. The power management system according to claim 10, furthercomprising: a dispensing unit for dispensing the respective vending itemand for generating one or more sound-based dispensing events indicatingthat the respective vending item is being dispensed, the dispensing unitincluding at least one of: (1) a dispensing port through which therespective vending item to be dispensed is passed for delivery; (2) anaccess unit that is operated for delivery of the respective vending itemto a patron; or (3) a mechanized unit that selects the respectivevending item from the vending items, wherein the audio signal detectorincludes a sound-based event detector disposed in a vicinity of one ormore of the dispensing port, the access unit or the mechanized unit tosense sound generated by the dispensing unit during a respectivesound-based dispensing event.
 12. The power management system accordingto claim 11, wherein the audio signal detector includes a noisecompensation unit that compensates for ambient noise, the noisecompensation unit changing a level of the detected audio signal thatindicates the respective sound-based dispensing event based on changesin ambient noise level.
 13. The power management system according toclaim 12, wherein the noise compensation unit includes a feedbackamplifier in a feedback loop of another amplifier to adjust a level of afeedback signal which is compared to the detected audio signal such thatthe level of the feedback signal corresponds to the ambient noise levelin the detected audio signal.
 14. A power management system for avending component within a vending machine that dispenses vending items,comprising: an audio signal detector for detecting an audio signalindicating a respective vending item is being dispensed and fortransmitting a dispensing event signal in accordance with the detectedaudio signal; and a controller for receiving the dispensing event signalfrom said audio signal detector and for selectively placing the vendingcomponent in one of a first operating mode or a second operating modebased on the received dispensing event signal, wherein in the firstoperating mode power supplied to the vending component is greater thanthe power supplied in the second operating mode.
 15. The powermanagement system according to claim 14, wherein the controllerincludes: a normal-operation controller for controlling operations ofthe vending machine in the first operating mode, as a normal operatingmode; and an override controller for overriding the normal-operationcontroller during the second operating mode, as a energy-savingsoperating mode.
 16. The power management system according to claim 15,wherein the override controller generates a control signal toselectively disable a supply of the power to the vending component. 17.The power management system of claim 14, wherein the audio signaldetector includes: an ambient noise compensation unit for compensatingfor ambient noise in the detected audio signal by changing a thresholdthat is compared to the detected audio signal.
 18. The power managementsystem of claim 17, wherein the ambient noise compensation unit includesan operational amplifier configured as an integrator and lowpass filterto generate the threshold from an ambient noise component of thedetected audio signal such that the detected audio signal is compared tothe threshold to generate the dispensing event signal.
 19. The powermanagement system of claim 14, further comprising: a time-of-year sensorfor dynamically changing a condition for placing the vending componentin the first or second operating modes based on at least one of: (1) oneor more predetermined times of a day; (2) one or more predetermined daysof a week; or (3) one or more predetermined holidays.
 20. A vendingmachine for dispensing a vending item, comprising: a vending componentwithin the vending machine; an audio signal detector for receiving anaudio signal indicating a respective vending item is being dispensed,for comparing the audio signal to a threshold, and for transmitting adispensing signal based on the audio signal exceeding the threshold; anda controller for receiving the dispensing signal from said audio signaldetector and for selectively placing the vending component in one of afirst operating mode or a second operating mode based on the receiveddispensing signal, wherein in the first operating mode power supplied tothe vending component is greater than the power supplied in the secondoperating mode.
 21. The vending machine of claim 20, wherein the audiosignal detector includes: an ambient noise compensation unit forcompensating for ambient noise by changing the threshold that iscompared to the detected audio signal.
 22. The vending machine of claim21, wherein the ambient noise compensation unit includes an operationalamplifier to generate the threshold from an ambient noise component ofthe detected audio signal such that the detected audio signal iscompared to the threshold to generate the dispensing signal.
 23. Thevending machine of claim 21, wherein the first and second operatingmodes are normal and energy-saving modes, respectively and the vendingcomponent is a cooling component of the vending machine.